Bethe was most active in the field of nuclear physics, where he made his
greatest contributions. In 1967, he was awarded the Nobel Prize for his 1939 work on the theory of nuclear processes which power stars (Physical Review
55:103, 434; see proton-proton chain for the details). His work
significantly advanced our understanding of atomic nuclei and their
interactions. He also
worked in the fields of solid state physics, atomic physics, and astrophysics.
Most recently, he appeared as a co-author on several papers relating to the
evolution of white dwarf, neutron star, and black holebinaries (e.g. Astrophysical Journal, v547, 345 in January 2001),
along with several other papers in recent years on supernovae,
gamma ray bursts, and neutrinos. As an aside, in 1948, he
lent his name to a paper by Ralph Alpher and George Gamow on
"The Origin of Chemical Elements" in the big bang known as the
"Alpher-Bethe-Gamow" (alpha-beta-gamma...) theory.

In addition to his work on nuclear, atomic, and astrophysical theory, Bethe
was an advocate for international arms control and the elimination of
weapons of mass destruction world wide. Like many of the scientists involved
with the Manhattan Project, Bethe was primarily concerned that the United
States develop atomic bombs before Nazi Germany could do so, but did not
wish to see them used in war. He actively opposed the
development of thermonuclear weapons and anti-ballistic missile technology,
as well as the proliferation of nuclear weapons technology. He
has been involved in the Pugwash Conferences and the
Union of Concerned Scientists. On hydrogen bombs he said

If we fight a war and win it with H-bombs, what history will remember is not
the ideals we were fighting for but the methods we used to accomplish them.
These methods will be compared to the warfare of Genghis Khan who
ruthlessly killed every last inhabitant of Persia.

Hans Bethe remained at Cornell for his entire career, and held the John Wendell Anderson (emeritus) Professorship of Physics. He is survived by his wife,
Rose (nee Ewald), and children Henry and Monica.

Sources: various, notably www.nobel.se and www.fas.org. His most noteworthy
scientific papers can be found in "The Selected Works of Hans A. Bethe".